<?php
namespace Leaps\Database\Eloquent;
use Closure;
use Leaps\Database\Query\Expression;
use Leaps\Database\Query\Builder as QueryBuilder;
class Builder
{

    /**
     * The base query builder instance.
     *
     * @var \Leaps\Database\Query\Builder
     */
    protected $query;

    /**
     * The model being queried.
     *
     * @var \Leaps\Database\Eloquent\Model
     */
    protected $model;

    /**
     * The relationships that should be eager loaded.
     *
     * @var array
     */
    protected $eagerLoad = array ();

    /**
     * The methods that should be returned from query builder.
     *
     * @var array
     */
    protected $passthru = array (
            'toSql',
            'lists',
            'insert',
            'insertGetId',
            'pluck',
            'count',
            'min',
            'max',
            'avg',
            'sum',
            'exists'
    );

    /**
     * Create a new Eloquent query builder instance.
     *
     * @param \Leaps\Database\Query\Builder $query
     * @return void
     */
    public function __construct(QueryBuilder $query)
    {
        $this->query = $query;
    }

    /**
     * Find a model by its primary key.
     *
     * @param mixed $id
     * @param array $columns
     * @return \Leaps\Database\Eloquent\Model static null
     */
    public function find($id, $columns = array('*'))
    {
        $this->query->where ( $this->model->getKeyName (), '=', $id );

        return $this->first ( $columns );
    }

    /**
     * Find a model by its primary key or throw an exception.
     *
     * @param mixed $id
     * @param array $columns
     * @return \Leaps\Database\Eloquent\Model static
     */
    public function findOrFail($id, $columns = array('*'))
    {
        if ( ! is_null ( $model = $this->find ( $id, $columns ) ) ) return $model;

        throw new ModelNotFoundException ();
    }

    /**
     * Execute the query and get the first result.
     *
     * @param array $columns
     * @return \Leaps\Database\Eloquent\Model static null
     */
    public function first($columns = array('*'))
    {
        return $this->take ( 1 )->get ( $columns )->first ();
    }

    /**
     * Execute the query and get the first result or throw an exception.
     *
     * @param array $columns
     * @return \Leaps\Database\Eloquent\Model static
     */
    public function firstOrFail($columns = array('*'))
    {
        if ( ! is_null ( $model = $this->first ( $columns ) ) ) return $model;

        throw new ModelNotFoundException ();
    }

    /**
     * Execute the query as a "select" statement.
     *
     * @param array $columns
     * @return \Leaps\Database\Eloquent\Collection static[]
     */
    public function get($columns = array('*'))
    {
        $models = $this->getModels ( $columns );

        // If we actually found models we will also eager load any relationships that
        // have been specified as needing to be eager loaded, which will solve the
        // n+1 query issue for the developers to avoid running a lot of queries.
        if ( count ( $models ) > 0 ) {
            $models = $this->eagerLoadRelations ( $models );
        }

        return $this->model->newCollection ( $models );
    }

    /**
     * Pluck a single column from the database.
     *
     * @param string $column
     * @return mixed
     */
    public function pluck($column)
    {
        $result = $this->first ( array (
                $column
        ) );

        if ( $result ) return $result->{$column};
    }

    /**
     * Get an array with the values of a given column.
     *
     * @param string $column
     * @param string $key
     * @return array
     */
    public function lists($column, $key = null)
    {
        $results = $this->query->lists ( $column, $key );

        // If the model has a mutator for the requested column, we will spin through
        // the results and mutate the values so that the mutated version of these
        // columns are returned as you would expect from these Eloquent models.
        if ( $this->model->hasGetMutator ( $column ) ) {
            foreach ( $results as $key => &$value ) {
                $fill = array (
                        $column => $value
                );

                $value = $this->model->newFromBuilder ( $fill )->$column;
            }
        }

        return $results;
    }

    /**
     * Get a paginator for the "select" statement.
     *
     * @param int $perPage
     * @param array $columns
     * @return \Leaps\Pagination\Paginator
     */
    public function paginate($perPage = null, $columns = array('*'))
    {
        $perPage = $perPage ?  : $this->model->getPerPage ();

        $paginator = $this->query->getConnection ()->getPaginator ();

        if ( isset ( $this->query->groups ) ) {
            return $this->groupedPaginate ( $paginator, $perPage, $columns );
        } else {
            return $this->ungroupedPaginate ( $paginator, $perPage, $columns );
        }
    }

    /**
     * Get a paginator for a grouped statement.
     *
     * @param \Leaps\Pagination\Environment $paginator
     * @param int $perPage
     * @param array $columns
     * @return \Leaps\Pagination\Paginator
     */
    protected function groupedPaginate($paginator, $perPage, $columns)
    {
        $results = $this->get ( $columns )->all ();

        return $this->query->buildRawPaginator ( $paginator, $results, $perPage );
    }

    /**
     * Get a paginator for an ungrouped statement.
     *
     * @param \Leaps\Pagination\Environment $paginator
     * @param int $perPage
     * @param array $columns
     * @return \Leaps\Pagination\Paginator
     */
    protected function ungroupedPaginate($paginator, $perPage, $columns)
    {
        $total = $this->query->getPaginationCount ();

        // Once we have the paginator we need to set the limit and offset values for
        // the query so we can get the properly paginated items. Once we have an
        // array of items we can create the paginator instances for the items.
        $page = $paginator->getCurrentPage ();

        $this->query->forPage ( $page, $perPage );

        return $paginator->make ( $this->get ( $columns )->all (), $total, $perPage );
    }

    /**
     * Update a record in the database.
     *
     * @param array $values
     * @return int
     */
    public function update(array $values)
    {
        return $this->query->update ( $this->addUpdatedAtColumn ( $values ) );
    }

    /**
     * Increment a column's value by a given amount.
     *
     * @param string $column
     * @param int $amount
     * @param array $extra
     * @return int
     */
    public function increment($column, $amount = 1, array $extra = array())
    {
        $extra = $this->addUpdatedAtColumn ( $extra );

        return $this->query->increment ( $column, $amount, $extra );
    }

    /**
     * Decrement a column's value by a given amount.
     *
     * @param string $column
     * @param int $amount
     * @param array $extra
     * @return int
     */
    public function decrement($column, $amount = 1, array $extra = array())
    {
        $extra = $this->addUpdatedAtColumn ( $extra );

        return $this->query->decrement ( $column, $amount, $extra );
    }

    /**
     * Add the "updated at" column to an array of values.
     *
     * @param array $values
     * @return array
     */
    protected function addUpdatedAtColumn(array $values)
    {
        if ( ! $this->model->usesTimestamps () ) return $values;

        $column = $this->model->getUpdatedAtColumn ();

        return array_add ( $values, $column, $this->model->freshTimestamp () );
    }

    /**
     * Delete a record from the database.
     *
     * @return int
     */
    public function delete()
    {
        if ( $this->model->isSoftDeleting () ) {
            return $this->softDelete ();
        } else {
            return $this->query->delete ();
        }
    }

    /**
     * Soft delete the record in the database.
     *
     * @return int
     */
    protected function softDelete()
    {
        $column = $this->model->getDeletedAtColumn ();

        return $this->update ( array (
                $column => $this->model->freshTimestamp ()
        ) );
    }

    /**
     * Force a delete on a set of soft deleted models.
     *
     * @return int
     */
    public function forceDelete()
    {
        return $this->query->delete ();
    }

    /**
     * Restore the soft-deleted model instances.
     *
     * @return int
     */
    public function restore()
    {
        if ( $this->model->isSoftDeleting () ) {
            $column = $this->model->getDeletedAtColumn ();

            return $this->update ( array (
                    $column => null
            ) );
        }
    }

    /**
     * Include the soft deleted models in the results.
     *
     * @return \Leaps\Database\Eloquent\Builder static
     */
    public function withTrashed()
    {
        $column = $this->model->getQualifiedDeletedAtColumn ();

        foreach ( $this->query->wheres as $key => $where ) {
            // If the where clause is a soft delete date constraint, we will remove it from
            // the query and reset the keys on the wheres. This allows this developer to
            // include deleted model in a relationship result set that is lazy loaded.
            if ( $this->isSoftDeleteConstraint ( $where, $column ) ) {
                unset ( $this->query->wheres [$key] );

                $this->query->wheres = array_values ( $this->query->wheres );
            }
        }

        return $this;
    }

    /**
     * Force the result set to only included soft deletes.
     *
     * @return \Leaps\Database\Eloquent\Builder static
     */
    public function onlyTrashed()
    {
        $this->withTrashed ();

        $this->query->whereNotNull ( $this->model->getQualifiedDeletedAtColumn () );

        return $this;
    }

    /**
     * Determine if the given where clause is a soft delete constraint.
     *
     * @param array $where
     * @param string $column
     * @return bool
     */
    protected function isSoftDeleteConstraint(array $where, $column)
    {
        return $where ['column'] == $column and $where ['type'] == 'Null';
    }

    /**
     * Get the hydrated models without eager loading.
     *
     * @param array $columns
     * @return array static[]
     */
    public function getModels($columns = array('*'))
    {
        // First, we will simply get the raw results from the query builders which we
        // can use to populate an array with Eloquent models. We will pass columns
        // that should be selected as well, which are typically just everything.
        $results = $this->query->get ( $columns );

        $connection = $this->model->getConnectionName ();

        $models = array ();

        // Once we have the results, we can spin through them and instantiate a fresh
        // model instance for each records we retrieved from the database. We will
        // also set the proper connection name for the model after we create it.
        foreach ( $results as $result ) {
            $models [] = $model = $this->model->newFromBuilder ( $result );

            $model->setConnection ( $connection );
        }

        return $models;
    }

    /**
     * Eager load the relationships for the models.
     *
     * @param array $models
     * @return array
     */
    public function eagerLoadRelations(array $models)
    {
        foreach ( $this->eagerLoad as $name => $constraints ) {
            // For nested eager loads we'll skip loading them here and they will be set as an
            // eager load on the query to retrieve the relation so that they will be eager
            // loaded on that query, because that is where they get hydrated as models.
            if ( strpos ( $name, '.' ) === false ) {
                $models = $this->loadRelation ( $models, $name, $constraints );
            }
        }

        return $models;
    }

    /**
     * Eagerly load the relationship on a set of models.
     *
     * @param array $models
     * @param string $name
     * @param \Closure $constraints
     * @return array
     */
    protected function loadRelation(array $models, $name, Closure $constraints)
    {
        // First we will "back up" the existing where conditions on the query so we can
        // add our eager constraints. Then we will merge the wheres that were on the
        // query back to it in order that any where conditions might be specified.
        $relation = $this->getRelation ( $name );

        list ( $wheres, $bindings ) = $relation->getAndResetWheres ();

        $relation->addEagerConstraints ( $models );

        // We allow the developers to specify constraints on eager loads and we'll just
        // call the constraints Closure, passing along the query so they will simply
        // do all they need to the queries, and even may specify non-where things.
        $relation->mergeWheres ( $wheres, $bindings );

        call_user_func ( $constraints, $relation );

        $models = $relation->initRelation ( $models, $name );

        // Once we have the results, we just match those back up to their parent models
        // using the relationship instance. Then we just return the finished arrays
        // of models which have been eagerly hydrated and are readied for return.
        $results = $relation->get ();

        return $relation->match ( $models, $results, $name );
    }

    /**
     * Get the relation instance for the given relation name.
     *
     * @param string $relation
     * @return \Leaps\Database\Eloquent\Relations\Relation
     */
    public function getRelation($relation)
    {
        $query = $this->getModel ()->$relation ();

        // If there are nested relationships set on the query, we will put those onto
        // the query instances so that they can be handled after this relationship
        // is loaded. In this way they will all trickle down as they are loaded.
        $nested = $this->nestedRelations ( $relation );

        if ( count ( $nested ) > 0 ) {
            $query->getQuery ()->with ( $nested );
        }

        return $query;
    }

    /**
     * Get the deeply nested relations for a given top-level relation.
     *
     * @param string $relation
     * @return array
     */
    protected function nestedRelations($relation)
    {
        $nested = array ();

        // We are basically looking for any relationships that are nested deeper than
        // the given top-level relationship. We will just check for any relations
        // that start with the given top relations and adds them to our arrays.
        foreach ( $this->eagerLoad as $name => $constraints ) {
            if ( $this->isNested ( $name, $relation ) ) {
                $nested [substr ( $name, strlen ( $relation . '.' ) )] = $constraints;
            }
        }

        return $nested;
    }

    /**
     * Determine if the relationship is nested.
     *
     * @param string $name
     * @param string $relation
     * @return bool
     */
    protected function isNested($name, $relation)
    {
        $dots = str_contains ( $name, '.' );

        return $dots and starts_with ( $name, $relation ) and $name != $relation;
    }

    /**
     * Add a relationship count condition to the query.
     *
     * @param string $relation
     * @param string $operator
     * @param int $count
     * @param string $boolean
     * @return \Leaps\Database\Eloquent\Builder static
     */
    public function has($relation, $operator = '>=', $count = 1, $boolean = 'and')
    {
        $instance = $this->model->$relation ();

        $query = $instance->getRelationCountQuery ( $instance->getRelated ()->newQuery () );

        $this->query->mergeBindings ( $query->getQuery () );

        return $this->where ( new Expression ( '(' . $query->toSql () . ')' ), $operator, $count, $boolean );
    }

    /**
     * Add a relationship count condition to the query with an "or".
     *
     * @param string $relation
     * @param string $operator
     * @param int $count
     * @return \Leaps\Database\Eloquent\Builder static
     */
    public function orHas($relation, $operator = '>=', $count = 1)
    {
        return $this->has ( $relation, $operator, $count, 'or' );
    }

    /**
     * Set the relationships that should be eager loaded.
     *
     * @param dynamic $relations
     * @return \Leaps\Database\Eloquent\Builder static
     */
    public function with($relations)
    {
        if ( is_string ( $relations ) ) $relations = func_get_args ();

        $eagers = $this->parseRelations ( $relations );

        $this->eagerLoad = array_merge ( $this->eagerLoad, $eagers );

        return $this;
    }

    /**
     * Parse a list of relations into individuals.
     *
     * @param array $relations
     * @return array
     */
    protected function parseRelations(array $relations)
    {
        $results = array ();

        foreach ( $relations as $name => $constraints ) {
            // If the "relation" value is actually a numeric key, we can assume that no
            // constraints have been specified for the eager load and we'll just put
            // an empty Closure with the loader so that we can treat all the same.
            if ( is_numeric ( $name ) ) {
                $f = function ()
                {
                };

                list ( $name, $constraints ) = array (
                        $constraints,
                        $f
                );
            }

            // We need to separate out any nested includes. Which allows the developers
            // to load deep relationships using "dots" without stating each level of
            // the relationship with its own key in the array of eager load names.
            $results = $this->parseNested ( $name, $results );

            $results [$name] = $constraints;
        }

        return $results;
    }

    /**
     * Parse the nested relationships in a relation.
     *
     * @param string $name
     * @param array $results
     * @return array
     */
    protected function parseNested($name, $results)
    {
        $progress = array ();

        // If the relation has already been set on the result array, we will not set it
        // again, since that would override any constraints that were already placed
        // on the relationships. We will only set the ones that are not specified.
        foreach ( explode ( '.', $name ) as $segment ) {
            $progress [] = $segment;

            if ( ! isset ( $results [$last = implode ( '.', $progress )] ) ) {
                $results [$last] = function ()
                {
                };
            }
        }

        return $results;
    }

    /**
     * Get the underlying query builder instance.
     *
     * @return \Leaps\Database\Query\Builder static
     */
    public function getQuery()
    {
        return $this->query;
    }

    /**
     * Set the underlying query builder instance.
     *
     * @param \Leaps\Database\Query\Builder $query
     * @return void
     */
    public function setQuery($query)
    {
        $this->query = $query;
    }

    /**
     * Get the relationships being eagerly loaded.
     *
     * @return array
     */
    public function getEagerLoads()
    {
        return $this->eagerLoad;
    }

    /**
     * Set the relationships being eagerly loaded.
     *
     * @param array $eagerLoad
     * @return void
     */
    public function setEagerLoads(array $eagerLoad)
    {
        $this->eagerLoad = $eagerLoad;
    }

    /**
     * Get the model instance being queried.
     *
     * @return \Leaps\Database\Eloquent\Model
     */
    public function getModel()
    {
        return $this->model;
    }

    /**
     * Set a model instance for the model being queried.
     *
     * @param \Leaps\Database\Eloquent\Model $model
     * @return \Leaps\Database\Eloquent\Builder
     */
    public function setModel(Model $model)
    {
        $this->model = $model;

        $this->query->from ( $model->getTable () );

        return $this;
    }

    /**
     * Dynamically handle calls into the query instance.
     *
     * @param string $method
     * @param array $parameters
     * @return mixed
     */
    public function __call($method, $parameters)
    {
        if ( method_exists ( $this->model, $scope = 'scope' . ucfirst ( $method ) ) ) {
            array_unshift ( $parameters, $this );

            call_user_func_array ( array (
                    $this->model,
                    $scope
            ), $parameters );
        } else {
            $result = call_user_func_array ( array (
                    $this->query,
                    $method
            ), $parameters );
        }

        return in_array ( $method, $this->passthru ) ? $result : $this;
    }
}
